SINGLE-ION CONDUCTIVITY IN POLY (LITHIUM PROPIONATE METHYL SILOXANE)

Poly(lithium propionate methyl siloxane )as a single-ion carrier source was synthesized. The crosslinked film showed lower lithium ionic conductivity at room temperature (about 10^(-10) S/cm). However,the lithium ionic conductivity was obviously increased by blending with high polar polymers such as polyethylene oxide, poly (methylsiloxane - co- ethylene oxide) and poly (methylsiloxane- g- ethylene oxide). In the blend system a high conductivity of 10^(-7)-10^(-5) Scm^(-1) at room temperature was obtained and the single-ion conductivity was deeply influenced by the content of the poly (lithium propionate methyl siioxane). The dc ionic conductivity of the flexible crosslinked films is more stable over time.

Synthesis of a Novel Core-shell Type Acrylic-polyurethane Hybrid Emulsion Containing Siloxane and Fluorine as well as Water and the Oil Resistances of Cured Film

Siliconated polyurethane （Si-PU） was synthesized using isophorone diisocyanate （IPDI）, hydroxybutyl-terminated polydimethylsiloxane （PDMS）, polytetramethylene ether glycol （PTMG）, polypropylene glycol （PPG）, 1,6-hexanediol （HDO）, dimethylol propionic acid （DMPA） and triethylamine （TEA）. Based on butyl acrylate （BA）, 2, 2, 2-trifluoroethylmethacrylate （TFEMA） and Si-PU as a seed emulsion, a novel core-shell type acrylic-polyurethane hybrid emulsion, containing siloxane and fluorine （F-Si-PU）, was prepared by seeded emulsion polymerization. The contents of siloxane and fluorine were determined according to the feed ratio. Fourier transform infrared spectroscopy （FTIR） was used to identify the chain structures of Si-PU and F-Si-PU. Investigation of transmission electron microscopy （TEM） confirmed the core-shell structure of F-Si-PU emulsion. Measurement results of water contact angle and the swelling ratio in water and n-octane for cured film showed that the water and the oil resistances for F-Si-PU had been significantly improved at a suitable content of fluorine and siloxane.

Synthesis and properties of acrylate latex modified by vinyl alkoxy siloxane

Acrylate latex modified by vinyl triisopropoxy silane (C-1706) was synthesized by seeded emulsion polymerization with anionic emulsifier sodium dodecyl sulphonate(SDS) and nonionic emulsifier OP-10 as the multiple emulsifiers at (78±2) ℃. The effects of different factors, such as the emulsifier, C-1706 monomer and its feeding manner on the properties of acrylate latex modified by C-1706 were investigated. The particle size distribution and the structure, the configuration, the weather durability and stain resistance of copolymer latex were characterized by particle size analyzer, Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope(TEM), scanning electron microscope(SEM) and ultraviolet aging instrument respectively. The results show that SDS to OP-10 as multiple emulsifiers can lead to coordinated efficiency, the optimal emulsifier dosage is 2.4%?3.2%(mass fraction), and the mass ratio of SDS to OP-10 is 1?1? 1?2. The seeded emulsion polymerization can effectively introduce a organic-siloxane bonding in a macromolecule inter polymer, and the obtained acrylate latex modified by organic-siloxane possesses narrow distribution of particle size with mean diameter of 51.8?76.6 nm and has the excellent properties in weather durability and stain-resistance especially.

Removal of siloxanes from biogas using acetylated silica gel as adsorbent

Biogas can be used as an alternative energy source for producing heat and electricity;however, volatile methylsiloxanes(VOSiC) present in biogas can severely damage heat exchangers, turbines and gas engines. Consequently, e cient removal of VOSiC from biogas that is used as a biofuel is required. In this work, acetylated silica gel(Ac@SG) was synthesized,via treatment of microporous silica gel(SG) with acetic anhydride as an adsorbent, for removal of VOSiC from biogas,and characterized with XRD, SEM–EDS, N2-BET and FT-IR. This Ac@SG adsorbent exhibited a meso-/microporous structure and hydrophobic surface, indicating it was a more e cient adsorbent for removing hexamethyldisiloxane(L2) and octamethylcyclotetrasiloxane(D4) from biogas samples than conventional SG. It was found that the adsorption capacities of Ac@SG reached 304 mg L2/g for hexamethyldisiloxane and 916 mg D4/g for octamethylcyclotetrasiloxane at lower temperatures in the experimental range, and water had no significant e ect on its absorption e ciency. The used Ac@SG could be easily regenerated by heating it at 110 °C, and the adsorption capacity of recycled Ac@SG for hexamethyldisiloxane and octamethylcyclotetrasiloxane was kept constant in four recycle adsorption experiments.

Evaluation on Self-healing Mechanism and Hydrophobic Performance of Asphalt Modified by Siloxane and Polyurethane

In order to inhibit and remove the thin ice and extend the lifetime of the damaged bridge, the self-healing mechanism and hydrophobic performance of asphalt modified by siloxane and polyurethane (ASP) were studied by dynamic shear rheology (DSR), fluorescence microscope (FM), atomic force microscope (AFM), the fracture-healing-re-fracture test and molecular simulations. The experimental results indicated that the selfhealing capability of ASP increased with increasing heating time and temperature. Furthermore, the addition of siloxane could improve the reaction energy barrier and complex modulus, and it is believed that the self-healing is a viscosity driven process, consisting of two parts namely crack closure and properties recovery. Contact angle of ASP increased with the increasing siloxane content and it deduced that the siloxane could improve the hydrophobic performance of ASP and the ASP molecule model could simulate well the self-healing mechanism and hydrophobic performance of ASP.

Investigation on poly[(methylsilylene ethynylene phenylene ethynylene)-co-(tetramethyldisiloxane ethynylene phenylene ethynylene)]

Poly[(methylsilylene ethynylene phenylene ethynylene)-co-(tetramethyldisiloxane ethynylene phenylene ethynylene)]was synthesized by polycondensation reaction of m-diethynylbenzene magnesium reagent with 1,3-dichlorotetramethyldisiloxane and dichloromethylsilane.The copolymer was characterized by FT-IR,~1H NMR,differential scanning calorimetry and thermogravimetric analysis.The results show that the copolymer exhibits good processability and cures at low temperatures.The cured copolymer shows high thermal stability.

STUDY ON SEGMENTED POLYURETHANE WITH MIXED SOFT SEGMENTS OF POLYCHLOROMETHYL METHYL SILOXANE AND POLYTETRAMETHYLENE OXIDE

Two series of polyurethanes based on mixed polychloromethyl methyl siloxane and poly-tetramethylene oxide in different weight fractions were synthesized. The phase separation ofsamples was studied using DSC and dynamic mechanical property analysis. The results showedthat the introduction of chloromethyl group into polysiloxane increased its polarity and henceimproved the miscibilities with polytetramethylene oxide and polyurethane hard segment.Particularly, in the case of N-methyldiethanolamine extended materials, the surface and tensileproperties of these samples can be adjusted by various ratios of two soft segments.

PREPARATION OF NANOMETER TiO_2 ORGANIC SOLUTION——EFFECT OF ORGANIC SILOXANE ON SOL PROPERTIES

A homogeneous longtime stabilized transparent nanometer TiO2 organic solution was obtained by means of the simultaneous hydrolysis and co-polycodensation of tetrabutyltitanate (TBT) and methacryloxypropyltrimethoxysilane (MAPTMS) by the sol-gel process. The particle size of nanometer titanium dioxide was controlled by use of bifunctional silanes, such as diphenyldimethoxysilane (DPDMS), diphenyldiethoxysilane (DPDES) and dimethyldiethoxysilane (DMDES). The effect of TiO2 content in the solution on the refractive index of system was discussed in detail. The result shows that the refractive index of solution increases linearly with TiO2 content. The refractive index of the three hybrid nanometer materials attained 1.6053, 1.5846 and 1.5346, respectively. The size of nanometer particles was characterized by TEM and the particle diameter thus obtained is in the range of 20-90 nm. FT-IR spectra of the materials show that the Ti— O—Si bond is formed.

Synthesis of Bioactive Gelatin-siloxane Hybrids for Bone Tissue Engineering and Evaluation of Its Drug Release Behaviors in vitro

Porous and bioactive gentamicin sulfate-loaded gelatin-siloxane hybrids were successfidly synthesized by using a combined sol-gel processing, post-gelation soaking, and freeze-drying process. A bone-like apatite layer was able to form in the Ca^2＋-containing porous gentamicin-loaded hybrids upon soaking in a simu- lazed body fluid （SBF） up to 1 day. The drug release of gentamicin sulfate was with a burst, followed by an almost constant release up to 7 days. And the rate of release in acidic medium was lower than that in the neutral and basic media.

Preparation of Rare Earth Doped Alumina Siloxane Gel and Its ER Effect

Poly(methyl methacrylate) (PMMA) was used to wrap alumina siloxane sol through emulsion polymerization. A kind of suspensions with notable ER effect was produced by fully mixing the prepared microcapsule with silicon oil. Meanwhile a series of PMMA wrapped alumina-siloxane gel doped with rare earths was obtained and its ER effect was tested, like viscosity of different rare earth ion doped samples in different powder concentrations and at different temperatures, at the same time, leak current density and dielectric constant were measured. Results show that the ER effect of this suspension is remarkable, and its stability is much better. The condition of emulsion polymerization and the mechanism of effect are discussed.

Thermal and Optical Properties of Epoxy/Siloxane Hybrimer Based on Sol-Gel-Derived Phenyl-Siloxane

A hybrimer based on epoxy resin and phenyl-siloxane was prepared by polymerization and a solgel condensation reaction in which Eporite-904 (807 g/eq) bisphenol-A-type epoxy resin, 3-isocyanatopropyltriethoxysilane (IPTES) and phenyltriethoxysilane (PTEOS) acted as precursors. The thermal and optical properties of the epoxy/siloxane hybrimer were studied. The thermogravimetric analysis (TGA) results implied that the hybrimer could increase the crosslink density and enhance the thermal properties. The optical properties were measured after thermal and UV aging. The refractive indexes of the epoxy/siloxane hybrimers were 1.66 - 1.70, and the transmittances of the cured hybrimers were above 90% in the visible wavelength. After a 120°C/24-h thermal aging test, the decreases in the refractive index and transmittance were less than 5% and 20% respectively. The epoxy/siloxane hybrimers also showed low discoloration upon thermal aging at 120°C for 24 h under an air atmosphere.

Synthesis of 1,1,3,3,5,5-hexamethyl-1,5-bis[(3-ethyl-3-methoxyoxetane)propyl]trisiloxane and Research on Its UV-curing Performance

A compound,3-ethyl-3-hydroxymethyloxetane(EHO),was synthesized with diethyl carbonate and trihydroxypropane as raw materials,3-ethyl-3-allylmethoxy oxetane(EAMO)was synthesized with EHO and allyl bromide,and 1,1,3,3,5,5-hexamethyl-1,5-bis[(3-ethyl-3-methoxyoxetane)propyl]trisiloxane(HMBEMOPTS)was synthesized with EAMO and 1,1,3,3,5,5-hexamethyltrisiloxane(HMTS).HMBEMOPTS is a novel UV-curable oligomer.The test of photo-DSC shows the photosensitivity of HMBEMOPTS is better than the ordinary oxetane,3-ethyl-3-[(3-ethyloxetan-3-yl)methoxymethyl]oxetane.HMBEMOPTS was mixed with bisphenol A type epoxy resin E-51 to prepare a cationic UV-curable system,and triarylsulfonium hexafluoroantimonate(UV-6976)was used as a cationic photoinitiator.The mechanical tests of coating films prove that when the mass fraction of HMBEMOPTS is 50%,the mechanical properties of the curing system are the best.The impact strength of the UV-curable films is measured to be 40 kg·cm and the flexibility is 2 mm;the tensile strength and flexural strength of the prepared specimens are 20.74 MPa and 13.43 MPa,respectively.The experimental results show that HMBEMOPTS can effectively improve photosensitivity and flexibility of the photosensitive resin.

ER Effect of PMMA Wrapped Alumina-Siloxane Gel Doped with Rare Earths

PMMA wrapped alumina siloxane gel was obtained by using poly (methyl methacrylate) (PMMA) to wrap alumina siloxane sol which was made from water glass, aluminum nitrate and α methacrylic acid. Meanwhile, rare earth ions were used to dope in the course of reaction, and stable suspensions was produced by putting PMMA wrapped microcapsule powder doped with rare earths into methy silicon oil. It is found that its electrorheological (ER) effect improves strikingly after loading electric field. At a certain concentration, the immediate viscosity increases from 95 to 178 Pa·s compared to the system without doping.

SHEAR WAVE ATTENUATION IN POLY (DIMETHYL SILOXANE) (PDMS)

A valid experimental setup was proposed to study the wave transfer in PDMS fluids. It is found that the degree of attenuation in strain rate is greater with the increasing fluid viscosity, increasing vibration frequency, and increasing wave traveled distance.

Structure and Properties of Silk Fibers Grafted with Vinyl Siloxane Monomer

Silk fibers were grafted with a novel vinyl siloxane monomer. The properties of silk with different grafting yield were discussed. The results showed that the crease recovery of grafted silk fabric is improved significantly, handle of grafted silk is softer, and grafting has no influence on strength of silk. Graft with low grafting yield has no effect on dyeing properties of silk. The results of IR, SEM photographs and amino acid analysis indicate that the monomer combines with silk fiber by physical sediment and chemical bond, the grafting reactions mainly occurred on Ser., His. and Arg. of silk fibers, and ester crosslinking forms between silanol and Asp., Gin. of silk molecular side chains. X-ray diffraction patterns of silk fibers suggest that the grafting has no effect on the crystalline regions.

NEW FLUOROSILOXANE AS A COATING MATERIAL FOR NERVE AGENT SENSORS

Polymer coated quartz crystal microbalance (QCM) sensor based on the frequency shifts due to the adsorption of compounds at the surface of modified quartz crystal electrode is an effective method for detection of sarin (GB) which is a highly toxic nerve warfare agent. A new fluorosiloxane polymer has been synthesized through 6 steps from trifluoromethyl benzene. The synthesis was achieved from trifluoromethyl benzene through nitration, hydrogenation. The obtained m-nitrotrifluoromethyl aniline was treated with NaNO2, and then hydrolyzed to m-nitrotrifluoromethyl phenol. m-nitrotrifluoromethyl phenol was reacted with allyl bromide to the ether product. The product was rearranged by Claisen rearrangement, and then reacted with polymethylhydrosiloxane under catalyst of Pt/DVTMS. The fluorosiloxane polymer can be obtained. The polymer has been successfully used as QCM coating material.

Investigation of volatile methyl siloxanes in biogas and the ambient environment in a landfill

Landfill biogas is a potential alternative for fossil fuel,but the containing impurities,volatile methyl siloxanes(simplified as siloxanes),often cause serious problems in gas turbines when applied to generate electricity.In this research,a collecting and analyzing method based on solvent adsorption and purge and trap-gas chromatography-mass spectrometry was established to determine the siloxanes in biogas from a landfill in Jinan,China,and adjacent ambient samples,such as soil,air,and leachate of the landfill.The results showed that,octamethylcyclotetrasiloxane(D4)and decamethylcyclopentasiloxane(D5)accounted for 63%of total siloxanes;and without considering D4 and D5,the order of detected siloxanes in concentration was found relating to Gibbs free energies of molecules,namely that higher abundant siloxane(except for D4 and D5)usually had lower Gibbs free energy.Additionally,the mass ratio between D4 and octamethyltrisiloxane(L3)in the bio gas varied with different garbage age in landfills,possibly revealing the breaking-down of larger siloxane molecules with time.The samples,which were collected from environmental samples adjacent to the landfill,such as soil,water,and air,presented much higher siloxane level than urban or rural area away from landfills.The current H2 S scrubber of the landfill biogas could decrease the total siloxanes from 10.7 to 5.75 mg/m^3 due to Fe2 O3 and a refrigerant drier in a purification system and cyclic siloxanes were more easily removed than linear ones.

Dielectric analysis on phase transition and micelle shape of polyoxyethylene trisiloxane surfactant in dilute aqueous solution

The cloudy Silwet L-77 aqueous solution on the concentration range from 0.5%to 50%was investigated by dielectric relaxation spectroscopy.The concentration dependence of phase microstructure was confirmed by means of analyzing the dielectric parameters of bulk solution.The relaxation behavior was assigned to the interfacial polarization between the micelle and the medium,and the relaxation distribution parameter was used to figure the shape transition from sphere to ellipsoid with the concentration increasing.The synchronous reduction of permittivity and conductivity indicated the formation of the lamellar phase. As compensation,the quantity of the surfactant liquid phase gradually decreased,whose shape constantly kept ellipsoidal.

Dual-Resistance of Ion Migration and Moisture Erosion via Hydrolytic Crosslinking of Siloxane Functionalized Poly(Ionic Liquids)for Efficient and Stable Perovskite Solar Cells

The inevitable ion migration that occurs within ionic polycrystalline perovskite film results in inferior longterm stability of perovskite solar cells(PVSCs)that cannot meet the commercial requirements.Here,a novel poly(ionic liquid)named poly-1-vinyl-3-propyltrimethoxysilane imidazolium chloride(PImIL-SiO)is first introduced into perovskite to strengthen grain boundaries(GBs)and construct dual-functional barriers against internal ion migration and external moisture erosion for fabricating highly efficient and stable PVSCs.PImIL-SiO-containing imidazoliumcations and pendant siloxane groups contribute to passivation of bulk defects and anchoring of GBs,which effectively hinders ion migration channels,thus reducing perovskite film phase separation and device hysteresis.Furthermore,the intrinsically hydrophobic PImIL-SiO automatically forms a secondary protective barrier to endow the perovskite film with ultrahigh moisture corrosion resistance through the hydrolyzation reaction of siloxane with the permeated moisture.Consequently,the PImIL-SiO-modified PVSCs achieve a champion power conversion efficiency(PCE)of 22.46%,accompaniedby excellent thermal andhumidity stabilities where the non-encapsulated devices retain 87%of the initial PCE after aging at 85℃for 250 h and>85%of the initial PCE over 1100 h in air with a relative humidity of 50–70%.

Research progress of siloxane removal from biogas

Siloxanes in biogas are detrimental to engine,turbine,fuel cell,etc.,thus it is necessary to remove siloxanes from biogas before biogas high-value utilization.At present,there are few domestic researches and related reports in view of siloxanes removal from biogas.This paper introduces the property of siloxanes as well as sampling and analysis method,and then presents the research progress of siloxanes removal from biogas.Three commercial technologies overseas are adsorption,absorption and cryogenic condensation.Among them,adsorption on activated carbon is the most widely used method.Other technologies,such as biological removal,catalytic processes,membranes,source controlling,etc.are under exploration and development.At last,this paper summarizes the advantages and disadvantages of siloxanes removal technologies as well as the applicability and analyzes the future research trend and emphasis.This paper could provide a reference in the field of biogas high-value utilization.